An attribute on the canvas element would presumably be equally applicable to all contexts. Is there a reason that it's better to have opaqueness specified at context creation time instead of on the canvas? Also, I think "opaque" is easier to understand than "alpha: false".
- Maciej On Mar 13, 2013, at 9:57 AM, Gregg Tavares <[email protected]> wrote: > It would be nice if this was the same as WebGL instead of different. > Especially because 2d canvas and WebGL need to inter-operate in the near > future. > > In WebGL to create a canvas with no alpha (an opaque canvas) you do this > > gl = canvas.getContext("experimental-webgl", { alpha: false }); > > Why can't 2D canvas be this > > ctx = canvas.getContext("2d", {alpha: false}); > > As for why this is important to be the same see the proposal for Canvas in > Workers here (http://wiki.whatwg.org/wiki/CanvasInWorkers) > > In that proposal the "backingstore" of a canvas can be moved to/from a > worker. That solution may or many not be the final solution but it points out > that whatever solution is chosen we need the solution to work for both canvas > 2d and WebGL and as such needs a common way to create backing stores with no > alpha. > > > > On Wed, Mar 13, 2013 at 9:30 AM, Dirk Schulze <[email protected]> wrote: > This is a very long thread and I did not see any conclusions or agreement on > this thread. Can you summarize the topic and the status on the acceptance > level please? > > Greetings, > Dirk > > On Mar 13, 2013, at 9:15 AM, Stephen White <[email protected]> wrote: > > > Hi WebKittens, > > > > I'm planning to implement the canvas "opaque" attribute, as proposed here: > > http://lists.w3.org/Archives/Public/public-whatwg-archive/2013Mar/0109.html. > > > > This is an attribute that causes the allocation of an opaque backing store > > for <canvas>, allowing optimizations at the time the canvas is composited > > into the page, such as disabling blending and culling obscured content. It > > is based on the moz-opaque attribute currently shipping in Firefox. > > > > I'll be placing the feature behind the build-time flag > > ENABLE(OPAQUE_CANVAS). > > > > Let me know if you have any comments or concerns. > > > > Stephen > > _______________________________________________ > > webkit-dev mailing list > > [email protected] > > https://lists.webkit.org/mailman/listinfo/webkit-dev > > _______________________________________________ > webkit-dev mailing list > [email protected] > https://lists.webkit.org/mailman/listinfo/webkit-dev > > _______________________________________________ > webkit-dev mailing list > [email protected] > https://lists.webkit.org/mailman/listinfo/webkit-dev
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